Varying lepton efficiencies
Bug #1436948 reported by
Jeff Asaf Dror
This bug affects 1 person
| Affects | Status | Importance | Assigned to | Milestone | |
|---|---|---|---|---|---|
| MadGraph5_aMC@NLO |
Invalid
|
Undecided
|
Unassigned | ||
Bug Description
Hi,
I've recently noticed that pythia-pgs has reduced lepton tagging efficiencies. I was wondering whether this was intentional. As a simple test I tried (with all default settings in SM file)
> generate p p > z, z > l+ l-
and running pythia-pgs. By checking the number of two lepton events in the final state in the LHCO file (8135 out of 10000) I calculate an efficiency of about 90%. This is in line with the value I expected.
However, if I run
> generate p p > z
and let pythia-pgs decay the Z I only find 319 out of an expected 688 events, corresponding to an efficiency of 68% (I've also ran this with higher statistics yielding similar results).
Is this an expected behavoir?
Revision history for this message
| Olivier Mattelaer (olivier-mattelaer) wrote | #1 |
| Changed in mg5amcnlo: | |
| status: | New → Invalid |
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Hi,
I have no idea and we will not be able to help you on this.
I would suggest that you contact the pythia author to know the difference of treatment between those two way to compute.
What is likely to be due to a difference of treatement in the invariant mass of the Z, Since in the first case the invariant mass is forced by a cut to be between +-15 times the width (the 15 number can be change in the run_card).
On the second case, MG generates the Z onshell, but it is likely that pythia changes the invariant mass.
Cheers,
Olivier